WASHINGTON, May 31 (Reuters) - U.S. lawmakers on Thursdaysaid they are united when it comes to keeping the Internet freefrom centralized control and preventing the United Nations fromgaining power over Web content and infrastructure.

The U.S. government wants to bring as much ammunition aspossible to a December meeting in Dubai where delegations from193 countries will discuss whether to hand governance of theInternet over to the United Nations.

The United States fears December's treaty-writing conferencecould turn the Internet into a political bargaining chip andcould empower efforts by countries like China, Russia and Iranto erode Internet freedoms and isolate their populations.

"We may have our differences on domestic telecommunicationspolicy, but having those policies decided at the internationallevel would be the worst thing that could happen,"Representative Marsha Blackburn said at a hearing before a HouseEnergy and Commerce subcommittee.

The Tennessee Republican commended the Obamaadministration's efforts to thwart giving an internationalgoverning body power over the Internet.

Vinton Cerf, regarded as one of the fathers of the Internetand now vice president and chief Internet evangelist at GoogleInc, cautioned that a move toward top-down controldictated by governments could hinder Internet innovation andgrowth.

A bipartisan group of lawmakers on Wednesday introduced aresolution to reject the proposed international takeover of theInternet and preserve the current "multi-stakeholder" model ofgovernance.

"In many ways, this is a referendum on the future of theInternet," Republican Representative Mary Bono Mack said atThursday's hearing.

"If this power grab is successful, I'm concerned that thenext Arab Spring will instead become a Russia Winter where freespeech is chilled, not encouraged, and the Internet becomes awasteland of unfilled hopes, dreams and opportunities," saidBono Mack, a sponsor of the resolution.

Social media sites Twitter, Facebook and Google'sYouTube played a big role in last year's "Arab Spring"revolution.

"LETHAL THREAT"

The Internet is currently policed loosely, with technicalbodies such as the Internet Engineering Task Force, the InternetCorporation for Assigned Names and Numbers and the World WideWeb Consortium largely dictating its infrastructure andmanagement. The United States holds significant sway with thosebodies.

When the delegations gather in Dubai in December, they willrenegotiate a U.N. treaty last revisited in 1988, and debateproposals that would consolidate control over the Internet withthe United Nations' International Telecommunications Union(ITU).

"During the treaty negotiations, the most lethal threat toInternet freedom may not come from a full-frontal assault butthrough insidious and seemingly innocuous expansions ofinter-governmental powers," said Federal CommunicationsCommissioner Robert McDowell.

Proposals out of the Middle East, McDowell said, wouldchange the definition of telecommunications in a way thatarguably would include the Internet, and would suddenly sweep anentire industry into the rubric of ITU rules.

The Republican commissioner blasted claims from ITUleadership that no nations have proposed expanding the ITU'sjurisdiction to the Internet.

"An infinite number of avenues exist to accomplish the samegoal, and it is camouflaged subterfuge that proponents ofInternet freedom should watch for most vigilantly," he said.

The lawmakers fear that countries like China, Russia, Iran,Saudi Arabia and others could politick smaller nations who havelittle interest in the issue to back them in giving them greaterability to isolate their populations and silence politicaldissidents.

The United States is concerned that authoritarian regimeswill campaign for their initiatives by promising to backproposals from developing countries that would like to seetariffs on content-heavy Internet companies such as Google,Facebook and Netflix.

"Some ITU officials have dismissed our concerns over theseissues as mere election year politics, and nothing could befurther from the truth," McDowell said. "The threats are realand not imagined."

RAMPING UP

The United States will step up its meetings with othercountries to thwart an expansion of ITU's authority, with about50 or so bilateral meetings to take place in the lead-up to theDecember talks.

"We're investing a lot of effort in trying to be in the bestpossible position to explain why these kinds of things would bea bad idea," Ambassador Philip Verveer, deputy assistantsecretary of state, said.

The United States on May 8 formed its core delegation ofgovernment officials who will head to Dubai, including membersof the State Department, Commerce Department, Department ofHomeland Security, Defense Department, FCC and NASA.